Grand-piano action.



C. KNOCH.

GRAN D PIANO ACTION.

APPLICATION FILED MAY 31. 1916.

1,216,701.- Patented Feb. 20,1917.

anvmwm Carl '(uoolg CARL KNOCH, OF NEW YORK, N. Y.

GRAN D-PIAN 0 ACTION.

Application filed May 31, 1916.

To all whom it may concern:

Be it known that I, CARL KNOCH, a subject of the Emperor of Germany,residing at New York city, county and State of New York, have inventedcertain new and useful Improvements in Grand-Piano Actions. of which thefollowing is a full, clear, and exact description.

This invention relates to improvements in grand piano-actions, butpertains more particularly to the hammer or hammer-shank operatingdevices which are set in motion when a key is depressed. My invention isdirected mainly to improve that part of the action intended to preventthe rebound ing of the repetition lever and also to prevent thechattering of the pivotally connected repetition lever and its support.

I will now proceed to describe my invention in detail, the essentialfeatures of which will be summarized in the appended claim, referencebeing had to the accompanying drawing, forming part hereof, wherein thesingle view is a sectional. side elevation of that portion of the hammeraction of a grand piano embodying my improvements.

As my improvement has for an object to improve the hammer actuatingdevice of a grand piano, I have illustrated only that portion of theaction of such a piano which will fully disclose my improvement.

In the accompanying drawing, the nu meral 1 indicates the hammer shankof a grand piano action, the numeral 2 indicates the repetition lever ofsuch an action, 3 the support for the repetition lever and 4 the jack.The hammer actuating mechanism, indicated in a general way by thenumeral 5, consists of the said support 3 and repetition lever and jack.When a key is depressed (a portion of such a key being indicated by 6)the hammer actuating mechanism 5 will be swung upwardly, thehammer-shank 1 being also swung upwardly, due to a contacting felt shoe7 which is carried by the shank 1. The shoe 7 is located in alinementwith the free end of the jack 4 which passes through a slot 8 in therepetition lever 2.

When a key 6 is depressed, the hammer actuating mechanism 5 will beswung upon the pivot 9, all of the members 2, 3 and 4 moving together,until the free end of the repetition lever 52 comes in contact with theSpecification of Letters Patent.

-turned to normal position by a small Patented Feb. 20, 191 '7. SerialNo. 100,933.

stop 10. At such time the repetition lever will come to rest, but thejack 4 will continue to move upwardly and raise the shoe 7 off therepetition lever 2; at about this time the arm 11 of the jack will comein contact with the stop 12. A continued upward movement of the support3 will cause the jack 4, or rather the end 13 thereof, to move away fromthe shoe 7, thereby allowing the hammer-shank 1, and hammer 11 thereofto drop. The jack 4 is pivotally connected at 15 to the support 3.

When playing rapidly the movement of the hammer actuating mechanism 5 isof course also rapid and more or less snappy; hence there is a tendencyfor the repetition lever 2 to chatter, said repetition lever beingpivotally connected at 16 to the support- 3. When a, key is depressedand the hammer actuating mechanism 5 swung upwardly, the repetitionlever 2 will be the first element to come to rest against its stop 10.Then the jack will escape from the shoe 7 and the hammer will drop.While the repetition lever 2 is at rest, the support 3 will continue toswing upwardly. After the jack 4 has been tripped, it will be respring18. A stop 19 attached to a part of the fixed supporting frame of themechanism determines the rest position of the jack 4.

To prevent the rebound and chattering of the repetition lever 2 as wellas the support 3, I interpose between said parts a cushioning orshockabsorbing element, which in this instance consists of a coil spring20 seated at one end thereof in a socket 21 in the support 3 and at theother end around a lug 22 on the repetition lever 2. The spring 20cushions the rebound of the repetition lever when it strikes the stop 10and also prevents the chattering thereof. It also acts to keep thesupport 3 and capstan screw 23 on the key 6 reliably in contact, thusaiding gravity in holding said support on its fulcrum withoutdisplacement. The spring 20 is placed under an increased pressure afterthe repetition lever strikes the stop 10, whereupon it will be slightlycompressed. While in the normal position, the spring 20 will tend toforce the repetition lever and support apart, but will exert morepressure upon the support 3 after the repetition lever strikes the saidstop 10. Hence at the time when rebounding or chattering usually takesplace during rapid playing, the spring 20 will be exerting its greaterpressure. Certain of the illustrated parts have not beenreiterredto, astheir .hinction and action is well known to those skilled in the art.The stop 2; acts to maintain the repetition lever and its support in acertain fixed relationship while the stop serves to maintain the jack 4:and shoe 7 in alineinent during their periods of idleness. In otherwords, the stop 241- prevents the pressure exerted by the spring 20 frombeing transmitted to the shoe 7, throughthe repetition lever during theperiod of idleness oftheihammer actuating inechanismfi.

Having'now described my invention what Copies of this patent may beobtained for five cents each, by addressing the I claim and desire tosecure by Letters Patent is:

A. v grand piano action which includes hammer-actuating mechanismcomprising a rail, a repetition lever pivoted thereto, a supportunderneath the lever and pivoted to the latter and having a downwardprojection located to rest on the capstan screw ofthe key and a springbetween said lever and support bearing directly against both these-partsand tending to separate them.

Signed at New York city N. Y., this 29 day of May, 1916.

CARL KNOCH.

"VVitnesses EDWA D A. JARVIS,

MAURICE BLoon.

Commissioner of 1 Eatents,

Washington, In 0;

